BRUNSWICK, Maine — One of two Brunswick men indicted by the federal grand jury last week for allegedly conspiring to defraud the Internal Revenue Service of hundreds of thousands of dollars claimed Wednesday that the charges are invalid because the IRS is unconstitutional.

David E. Robinson, 75, said Wednesday that he will not appear in court Friday morning to face charges of conspiracy to defraud the United States by impeding and impairing the IRS.

F. William Messier, 70, who is charged with the same crime, as well as with failing to file federal tax returns and failing to pay federal income tax on nearly $400,000 from rental space on communication towers he owns in Brunswick, also will not appear, according to Robinson.

Messier could not be reached for comment on Wednesday, but Robinson provided a copy of a letter the two men sent to U.S. District Court Clerk Christa Berry in response to a criminal summons compelling them to appear on Friday.

In the letter, Robinson argues that the federal grand jury process that led to his and Messier’s indictment was unconstitutional and improperly targeted.

“If it was your intention to address this correspondence to [Robinson and Messier], it is obviously a mistake and incomplete, as there is no compliance and extradition order allowing you to address living inhabitants of a foreign state, and no penal bonds were attached for our action, and no official copy of any charges recorded by a court of record were presented,” the letter states.

Robinson said that the summons was addressed to his “legal, fictional identity” because “the court is a fictional entity limited to addressing only fictional entities.”

“The federal government is a for-profit corporation that is illegally occupying the seats of Congress of Washington, D.C.,” he said. “They have established fictional mirror-images, or clones, of each live person … but Mr. Messier and I are flesh-and-blood living persons.”

Robinson, who — in part — distinguishes between his real identity and “fictional” identity by using uppercase letters for one and lowercase letters for the other, is the author of the 2012 book, “Maine Lawsuit Against The IRS: For Unfair Trade Practices.” He said Wednesday that he was elected attorney general of the Maine Republic Free State Trust, but he declined to say how many members the trust includes. He said he has had no correspondence with national Sovereign Citizen groups or the Constitutional Coalition, a Maine group that has similarly questioned some aspect of the federal government’s authority.

The federal government claims that Messier earned more than $390,000 in gross income from renting antenna space on radio communication towers he owns on Tower Lane, off Hillside Road, and renting access to his property to customers who built their own communications towers or located electronics equipment on the property.

Last week, U.S. Attorney Thomas E. Delahanty said that after the IRS sent notices of levy to Messier’s customers, Robinson and Messier took a number of steps beginning in 2012 to obstruct and impede the IRS, including presenting the IRS with a worthless money order for the amount Messier owed and sending threatening and harassing documents to Messier’s customers urging them not to cooperate with the IRS.

Messier reportedly has not filed a federal income tax return since 1997, though the IRS assessed taxes, interest and penalties against him for $172,000 for the years 2000-04, according to Delahanty.

If either of the men fails to appear before U.S. Magistrate Judge John H. Rich III, a warrant could be issued for his arrest, according to the summons.

Pending legal action against the two men is concerning for groups whose radio equipment is stationed on Messier’s towers.

Joseph Randall of the Merrymeeting Amateur Radio Association said Wednesday that an attorney has advised the group to remove its equipment from Messier’s towers before Messier’s scheduled Friday morning court appearance, on the chance he doesn’t appear.

“If we don’t, our equipment could be impounded or we could be denied access because of his ongoing legal problems,” Randall of Phippsburg said Wednesday. “And we don’t have the kind of funds to fight it.”

The towers also support Brunswick and Freeport police and fire communications equipment, which is worrisome to local officials.

“We’re aware of the ongoing situation with Mr. Messier and his property, and we are looking into all available options,” Deputy Chief Marc Hagan of the Brunswick Police Department said Wednesday.

Messier faces up to 13 years in prison and fines totaling $1 million if convicted on all counts.

Robinson faces up to five years in prison and a fine of up to $250,000.